Screw-driver.



Patented May 31, 1904.

UNITED STATES 'PATENT Clarion.

OLOF OHLSON, OF NEWTON, MASSACHUSETTS.

SCREW-VDRNER.

SPECIFICATION forming part of Letters Patent N0. 761,391, dated May 31, 1904.

` Application iiled January 4, 1904.

, T a/ZZ whom, t may concern.'

Be it known that I, OLoF OHLsoN,'of Newton, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Screw-Drivers, of which` the following is a specification.

This invention relates to a screw-driver .having a removable shank or screw-engagin g portion which is detachably connected with the body or handle portion of the screw-driver and is adapted to be reversed, so that either, end may be utilized.

The invention is particularly adapted and intended for screw-drivers of small size, such as are used by watchmakers, although the invention is not necessarily limited to such use.

The invention has for its object to insure a firm connection of the removable shank with the body or-holder, so that there will be no possibility of a loose motion ofthe shank, the

y construction at the same time being such as to permit the quick and convenient release and attachment of theshank.

The invention consists in the improvements which I will now proceed to describe ,and claim.

Of the accompanying drawings, forming a part of this specification, Figure lrepresents a side elevation lof a watch screw-driver embodying my invention. Fig. 2 represents an enlarged sectional view of a portion of the same. Fig. 3 represents a side view of a part of the handle or body portion of the screwdriver; Fig. 4 represents asection on line 4 4 of Fig. 3. Fig. 5 represents a section on line 5 5 of Fig. 4. Figs. 6 and 7 represent sections on lines 6 6 and 7 7 of Fig. 5.

The same reference characters indicate the same parts'in all the figures.

In the drawings, a represents the body or handle portion of ascrew-driver, the same being in this embodiment of my invention formed in a single elongated substantially cylindrical piece of suitable metal, such as steel, the periphery of the said body being preferably longitudinally iuted to facilitate the grasping and rotation ofthe body by the thumb and finger of the operator. In one of the end portions of the body is formed a cylindrical socket or cavity b and a longitudinally-extending slot c, which is narrower than the diameter of 'the cavity Serial No. 187,610. (Nounodel.)

, and extends abovefthe bottom or inner end of the cavity, the said slot dividing the wall of the socket into two'resilient jaws 6252, having semicylindrical inner faces adapted to grasp a cylindrical'shan-k d. The portion of the slot that extends above the bottom of the socket subdivides the portion of .the body immediately above the socket into two resilient supplemental jaws b3 b3, having-flat faces formed by the sides of the slot, the said faces being adapted to bear on either of two flat-sided terminals d', formed on the end portions of the shank d. `I

. The fiat sides 8 8 of the terminals d are inclined relatively to each other and to the axis of the shank 'd in such manner that each terminal isl wedge-shaped, its thickness being gradually reduced from its inner to its outer portion. The 'thickness of the inner portion of each terminal is somewhat greater than the width of the slot c, so that when the shank is. inserted in the Acavity @the terminal d at its inner end will partially enter the space between the supplemental jaws b3 above the socket, the base portion of the terminal being wedged between the supplemental jaws and prevented from further inward movement before the upper portion of the terminal can portion of the shank CZ and the side's of the terminal d. As here shown, this result is eected by a collar e, adapted to slide on the tapered portion of the body and having a friction'al engagement therewith, said collar being formed so that when moved upwardly on the tapered portion of the body it will exert inward pressure on the said jaws.

Before inserting a shank Z in the socket the collar e is removed or loosened, and the shank is then inserted, the inner terminal d entering and being wedged between the supplemental jaws d3.' The collar e is lthen forced upwardly until the jaws b2 are pressed firmly against the cylindrical portion of the shank and the jaws 3 against the sides o f the terminal d. It will be seen that the lshank is IOO IO made by cutting a cylindrical metal rod into sections and flattening the end portions to form the terminals d.

I claim-- A screw-driver comprising, iirst, a body having an externally-tapered end portion containing a socket-cavity and a longitudinal slot narrower than the cavity and extending through the wall and above the bottom of the latter, the said slot subdividing the wall of 20 the Cavity in to resilient jaws having inner faces formed to grasp a shank, the slot also subdividing the portion of the body immediately above the cavity into supplemental jaws formed to engage a terminal on said shank; secondly, means for forcing said jaws inwardly to close them simultaneously upon said shank and terminal, and, thirdly, a cylindrical shank formed to be removably inserted in the socket and having Hattened inclined sides at its end portions forming wedge shaped terminals, either of which is formed to enter the slot bctween the supplemental jaws, cach terminal being thicker at its base portion than the width oi" the slot, so that the base of the terminal is wedged in the slot.

In testimony whereof 1 have aiiixcd my si gnature in presence of two witnesses.

' OLOF OHLSON.

Witnesses:

E. A. MARSH, C. L. ADAMS.

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